TYPICALLY, OCEANOGRAPHERS LOOK TO THE SEA. And they ask questions about how the wind, the waves, the continents, and the atmosphere affect the physics, chemistry, and biology of the oceans. They study temperature and salinity, which are controlled primarily by the interaction of the ocean, the atmosphere, and the land. And they study sunlight, the energy source that warms the sea and drives photosynthesis, the basis for life on this planet.

As they expand our understanding of the sea, oceanographers strengthen our nation in many ways, enabling us to develop the resources of our coastal waters, to improve our forecasts of weather patterns and storm events, and to prepare our military to operate on, under, and above the world's oceans.

Oceanographers who study the Chesapeake Bay ask many of the same questions they ask of the sea: questions about temperature, salinity, and light, and how these interactions drive the Bay's ecosystem. But they also ask: how does the land alter the Bay? How does the flow of water and earth coming off this huge and heavily populated watershed affect conditions in the Chesapeake?

Over time this landscape changed. Much of the forestland gave way to farmland, and much of the farmland gave way to industrial, urban, and suburban developments. In building Maryland's modern economy, we engineered our streams to serve our needs. We built dams to power our mills and generate electricity, we drew drinking water for cities, cooling waters for power plants and industry, and irrigation for agriculture. Into those rivers, we sent sewage from our cities, pollutants from our industries, and runoff from farms. These efforts seemed essential for growth and development, but they altered — in ways we did not fully understand — how the water runs off of the land and into our Bay.

As the flow off the land changed, the Bay changed. Sea grasses and shad and oysters, once abundant, declined, while other plants and animals, some of them invasives, became plentiful. Algae and plankton proliferated, and dead zones of no oxygen made annual appearances in the Bay's mainstem and its major rivers.

Now, oceanographers and estuarine scientists are examining how we might re-engineer our rivers and streams in ways that enable us to maintain a strong economy and achieve a sustainable ecology for the Chesapeake Bay. They are looking farther upestuary, probing into the "subestuaries" of our rivers, including the Potomac, the Choptank, and Maryland's largest, wholly own, Patuxent River. And they ask the tough question: What are the consequences of how our streams and rivers connect the land to the Bay and to the ocean?

This issue of Chesapeake Quarterly takes a look at the relatively new science of stream restoration. We are highlighting the new generation of estuarine scientists who are teaming up with hydrologists and geomorphologists, scientists who specialize in tracing the small waterways that flow downstream from the land to the sea. They are designing and debating strategies for retaining rainwater on the land, for slowing river flow, for replenishing groundwater, and for reducing the urban, suburban, and agricultural runoff of sediments and nutrients into our waterways. These strategies, researchers hope, could contribute to much-needed progress toward improving water quality in the streams and rivers that flow off our land into the Chesapeake Bay.

At the end of March, a new blog called On the Bay was launched as a service from Maryland Sea Grant and Chesapeake Quarterly magazine. Posts will include short essays, slide shows, podcasts, occasional videos, and frequent reporting on marine and environmental issues. From time to time we will carry guest-written posts contributed by those with Bay memories to share and by those engaged in studying, managing, or protecting the Chesapeake Bay's ecosystem.